Irradiance
by BlueNeutrino
Summary: When Geralt starts to suffer unexpected side effects from his use of mutagens, he reaches out to Regis for help. The affliction turns out to be even more unusual than initially thought, though, perhaps, Regis' way of looking at it makes Geralt think it may not be all bad.


"Regis, can I talk to you?"

At the sound of Geralt's voice, the vampire looks up from the book he'd been perusing and glances towards the doorway. Surely, he must have heard the witcher coming, yet nonetheless an uncharacteristic look of surprise crosses his face. His eyes widen minutely before he composes himself, then sets the book to one side and gestures for Geralt to enter.

"But of course, my friend. Do come in. Tell me what's on your mind."

A look of mild concern crosses the vampire's face as Geralt takes an unusually unsteady step into the room. "That mutagenerator you gave me," the witcher begins. "It's supposed to transmute the essence of dead monsters into mutagens at random, right?"

"That is its intended function, yes." Regis can't help the hand that extends to hover near Geralt's shoulder as he thinks the witcher seems unsteady on his feet. "Though, as an experimental prototype, it may well also operate in other ways that I haven't predicted. Please, take a seat, Geralt." He gestures at the couch, which the witcher seems all too happy to sink down onto.

"And the mutagens it produces are meant to be red, green, or blue?"

"I know of no others. The random nature of their generation may in actuality prove to be pseudo-random, though I haven't yet been able to discern the pattern. Has it malfunctioned?"

"You tell me." Geralt puts a hand to his face and rubs at his eyes. "Charged it with ekimmara essence yesterday. Produced what I thought was red mutagen, but after I took it something didn't seem right. Been seeing these white flashes and spots ever since." A grimace contorts his face as he pulls his hand away, then blinks. "They won't go away, even if I close my eyes."

"And you believe whatever was produced in the mutagenerator is to blame?"

"Seems likely," Geralt grunts, and he sounds very tired. "I hoped you'd maybe have an explanation of some kind. I just really need this to stop."

A frown creases Regis' brow as he leans in, studying Geralt more closely. There's a pang of guilt as he realises this is his fault. "I'm sorry, Geralt. I hadn't considered my device would have an adverse effect on you. That wasn't my intention."

"Hey, I've made a bad potion or two before. Sometimes stuff just goes wrong." He groans and blinks again. "Though I'd appreciate if there's anything you can do. Starting to get nauseous now."

Regis fixes him with a steady gaze, calm and thoughtful. "Well, whatever substance was produced by the apparatus, it has certainly had a remarkable effect on your blood."

"I take it you can smell it?"

"Indeed I can. Though, more to the point, I can see it."

Another blink, though this time one of confusion. "See it?"

"Yes. I had wondered if you were able to perceive it yourself, though perhaps it is beyond the limits of even your enhanced vision. Your blood appears to have developed irradiant properties. It shows quite starkly through your skin."

Geralt stares at him. "Well, that explains the look I got when I walked in."

"I must admit, it took me quite by surprise." Regis kneels in front of him then reaches for Geralt's hands, turning them palm-upwards before pushing back his sleeves to expose his wrists. "The glow is beyond the spectrum a normal human can perceive, though it's possible your witcher's eyes may catch a glimmer of it. To me, it is quite vivid."

Geralt squints and stares down at his own wrists, where the skin is thin and veins close to the surface. He tries to focus, wondering if he could catch the faint glow Regis speaks of, but if it's there, the painful white glare at the edges of his vision drowns it out. "Sorry, Regis. Really can't see much but flashing lights right now."

That gets a look of sympathy. "I'm sorry, my friend. That must be quite uncomfortable. If you'll allow me a closer look, I'll see if there's anything I can do."

He rises and moves to the various candles situated about the room, extinguishing them one by one. There are no windows for natural light: the room is underground, adjacent to a crypt, and Geralt grimaces as the darkness only makes the flashes in his vision worse. "Took Cat earlier," the witcher says, feeling foolish. "Thought it would help, but it only did the opposite." It might also, perhaps, be what allows him to still make out the vampire's silhouette in the dimness, but with everything else, Geralt doesn't think it's worth it.

"Yes, I can see how a potion designed to allow you to see in the dark would exacerbate the problem," Regis remarks, holding a lone votive candle encased in a glass sphere as he crosses back to the witcher. "Though, I suspect this is not how the symptoms initially manifested?"

"No. At first it was shadows, things not quite coming into focus. Then it was the flashes and white spots."

"Hmm." The vampire makes a thoughtful noise as he kneels in front of Geralt again. Then, very carefully, he reaches out with a clawed thumb and tugs at Geralt's eyelid, moving the candle in front of his face. "Do tell me if this hurts. I don't wish to cause you more discomfort."

Geralt grunts. The light makes his eyes ache, but it's no worse than it's been for the past several hours.

Regis watches the reaction of his irises, the slits narrowing as he passes the light across Geralt's vision. Fine, glowing filaments pulse feintly in his sclera, and Regis thinks if they weren't so vibrant, his eyes would look bloodshot. "These flashes you're seeing: are they sporadic, or quite regular?" he asks.

"Regular," Geralt answers, then gives into the urge to blink as Regis pulls back before switching to the other eye.

A minute or two passes as Regis continues to examine his eyes, careful to never let the sharpened point of his nail make contact with Geralt's skin, then he eventually lowers his hand. "I suspect I can identify the source of the problem," the vampire reports back, and it comes as a relief. "It appears that your retinas are, to some degree, sensitive to the radiation being emitted by your blood. What you're seeing is the glow from the blood vessels in your eyes flashing with your pulse, while the membrane at the back of your eyes amplifies the effect."

Geralt squints at him, then groans. "So that's why it doesn't go away when I shut my eyes." He hangs his head, shoulders slumping in exhaustion. Regis wonders how long it's been since he slept. "How long until it wears off?"

"I'm afraid I can't tell you. The effects of this mutagen are as unfamiliar to me as they are to you. Though, will a full examination, I could hopefully know more."

Geralt draws a breath then looks up at him. "Full examination?"

"There may well be other effects this unknown substance is having on your body. You seem to be quite tired."

"It's these damn flashes. I can't rest."

"If I learn more, perhaps I could find a way to help."

It makes sense. The witcher heaves a sigh and rubs at his eyes again. "Alright. Do it."

He leans back as Regis stands to bring over a chair to sit beside him. "Remove your shirt and lie down, Geralt, if you would. This shan't hurt. We are quite fortunate that, in this case, the symptoms themselves provide a valuable diagnostic tool. Observing the blood flow through your vital organs will be most informative."

Geralt does as he's asked, breathing deeply and lying back as Regis draws the chair closer and takes a seat beside him. The room is still dark, but between the white flashes invading his vision with every heartbeat, he can still see well enough.

For what feels like an age, Regis doesn't move. He simply sits, eyes panning over Geralt's body long enough that the witcher starts to grow uncomfortable. Geralt swallows, stares in the general direction of the vampire's motionless silhouette. "Yeah, I know. Gotta look like a veritable fountain of wine to you right now."

There's a pause, then Regis lifts his head. There's still only one candle alight in the room, but the motion brings his face into focus, meeting Geralt's eyes. "That isn't at all the thought that crossed my mind."

"No?"

"Actually, I was contemplating how incredibly beautiful it is."

The statement catches Geralt off guard. He's physiologically incapable of blushing, yet lying here, exposed, his very blood visible to the vampire, it feels like the same thing. "Beautiful, huh?" He sounds dubious.

"Yes. You should see yourself, Geralt. Your body is remarkable. I can see the blood entering each chamber of your heart as it beats; watch it pump life throughout your body with such power and efficiency. Every part of you is enhanced, allowing you to achieve feats beyond normal human limitations, and were it not so, I doubt the irradiance would have such a pronounced effect. The way your blood vessels are structured is quite the marvel."

There's something in his voice that Geralt can only describe as quiet awe. He glances down at his own chest, and thinks maybe he can see the faint glow beneath his sternum. "So, uh, apart from the glowing, everything working as it should?"

Only then does Regis move, as if finally remembering what he's meant to be doing. "Your liver is certainly glowing quite brightly," he remarks, placing a hand over the organ. "Though I suspect that is largely due to it working to cleanse your blood of the Cat potion you imbibed. Your heart, too, is highly luminous, though I would be concerned if it weren't. Other than the spots in your vision, have you experienced any other symptoms?"

Geralt groans and shuts his eyes. "Well, there's the headache. Started a couple of hours after the flashes did."

A hand comes to rest on his scalp, but there's no complaint from the witcher as Regis gently tilts his head, no doubt watching the blood. "What I suspect is a normal and healthy reaction to ocular overstimulation," he posits after observing it for a while. "I see no abnormalities in your brain. Indeed, other than this peculiar new property of your blood, I can detect no pathologies."

Sighing, Geralt cracks his eyes open again. "Great. So how do I reverse it?"

"I'm afraid I can't say. Though, since the same mechanism generated the mutagens you regularly use without trouble, I expect this side effect will eventually wear off. In the meantime, I would recommend sleep."

Another groan escapes the witcher's throat. "That's just it, I can't sleep. These damn blinking spots are keeping me awake."

"Then I shall prepare a sleeping draught," Regis says, rising from the chair. "If you still have concerns about any other unforeseen effects of this unknown mutagen, you may stay here while I keep an eye on you." He reaches for a box of matches from inside his desk drawer to begin lighting the candles again, then pauses. "In fact, I would be more comfortable if you did."

Geralt grunts. "Alright," he mutters, and thinks he really would rather keep Regis nearby for his own peace of mind. "If I'm staying here, Yennefer…"

"I shall send a raven to Yennefer," Regis says, anticipating his next few words. "Let her know you're safe with me. Have you mentioned this affliction to her?"

The corners of Geralt's mouth turn up. "She's the one who pushed me to come over here. Said if I'm having migraines, why don't I see the local barber-surgeon, and if it's the local barber-surgeon's fault, he can bloody well fix it." He sighs and rubs at his eyes again. "Then she threatened to take the mutagenerator away, until I persuaded her it's just one glitch I'm sure you could straighten out. And if you can't, she says she's going to bring the damn thing over here and smash it over your head."

Regis chuckles. "Well, that is certainly incentive for me to find you an effective cure," he says, finishing with the last candle. "Though, in all seriousness Geralt, I think you needn't worry. Your body is a remarkable organism. It will adapt and settle down soon enough."

"I was hoping for emphasis on the 'soon'," Geralt says, shutting his eyes, then feels Regis' hand on his shoulder. He cracks them open again just a fraction to see Regis holding a potion vial under his nose.

"Take this for the pain," the vampire says. "The sleeping draught will be ready shortly."

It is. The painkiller has taken the edge off the headache by the time Regis presents Geralt with a cup of the potion and has him sit down on the mattress on the floor. The witcher gulps it down quickly, ignoring the fact it hasn't cooled completely and the heat burns his tongue.

He lies down, his head sinking onto the bundle of blankets serving as a pillow before he notices Regis pulling up a cushion to sit beside him. "You gonna stay there the whole time?" he asks, surprised.

"I promised to keep an eye on you, Geralt. I can do that best from your bedside."

Geralt is touched, and less unnerved by the thought of someone watching him sleep than expected. He supposes it's a sign of just how much he's come to trust Regis. "How long am I gonna be out for?"

"No less than eight hours, though no more than fourteen. Adequate time, I hope, for the side effects to wear off."

Geralt groans. "Long time for you to just have to sit there. Sorry to be a nuisance."

"Not at all, Geralt," Regis dismisses, and begins to pull up a blanket to cover the witcher's tired body. Geralt has begun to feel the weight of the potion dragging on his eyelids. "I feel partly responsible for your current predicament, and this is the least I can do to help. Besides…" He places a gentle hand on Geralt's chest, cradling his heart. "This may be a valuable opportunity for me to study your internal organs in more detail. It will certainly assist me greatly in treating you in future. Your heart, in particular..."

He trails off, and Geralt thinks the gentle drag of his thumb across his chest is almost a reverent caress. Regis is staring somewhere below his collarbone, wide-eyed, awestruck.

Even with sleep rapidly creeping up on him, Geralt is struck by the realisation. "You really do think it's beautiful, don't you?"

"But of course." Regis looks up and meets his eyes. "Your heart is a thing of beauty keeping you alive, and even with my own enhanced senses I've never seen it quite like this. It is...dear to me, Geralt." He swallows, struggling to express his feelings about Geralt's mortality, how short his lifespan is compared to that of a higher vampire. Thinking about it too much is painful. "I treasure each heartbeat you've been given as another moment I'm able to spend with you, and here I am, able to see each one. I confess, it's had a profound effect on me." A look of doubt and self-consciousness briefly crosses his face, then he shakes his head. "Or perhaps I'm making far much more of this than I should. Never mind. Don't trouble yourself with my fancies, Geralt. Sleep."

There's a warmth seeping through Geralt's chest that he isn't entirely sure is an effect of the sleeping draught. He tries to find the words to respond, though he's really not going to win the fight against the potion for much longer. "Regis…"

"Shh." The vampire's voice is soothing. " _Sleep_."

Geralt closes his eyes. There are white flashes at the corner of his vision, his pulse beats in his ears, then finally, blissful, peaceful darkness.


End file.
